1. Login to  admin panel and then go to translation manager (yourdomain.com/translations or yourdomain.com/public/translations)
  2. Select modules group from the dropdown. If you do not see it in the dropdown then click Import groups button on top.
  3. All the frontend text is mentioned with values like front.XXXXXX
  4. Update the text and click Publish Translations on the top to save the changes.
  5. Check the documentation to know more about the translation manager.